Gia Nadareishvili was a famous endgame studies composer and co-founder, with John Roycroft and others, of PCCC (Permanent Commission for Chess Composition).
He wrote some books about chess studies: "Этюд глазами гроссмейстеров" (a compilation of studies commented by o.t.b. Grandmasters, 1982) or "Шахматный этюд в Грузии" (compilation of studies by Georgian authors, 1975) or "Избранные этюды" (125 studies by himself, 1970).